Thermarest Boost 650 32F/0C Sleeping Bag

Comfort isn’t one-size-fits-all, which is why the Boost 650 is designed to let you tailor its shape for the perfect balance of space and warmth. As a roomy semi-rectangular sleeping bag, it gives you the freedom to side sleep, shift positions, and stretch out without feeling restricted—offering significantly more space than a traditional mummy bag. But extra room requires more body heat to stay warm, and that’s where WarmZip technology comes in.

By zipping up the WarmZip center zipper, the Boost 650 transforms from a spacious semi-rectangular bag into a thermally efficient mummy shape. This adjustment pulls the 650-fill down insulation closer to your body, reducing the space that needs to be heated and boosting warmth by up to 10°F (6°C). Additional warmth-enhancing features—like a plush draft collar, a full-length draft tube, and a cinchable hood—ensure ultimate comfort throughout the night.

The Boost 650 isn’t just about sleeping—it’s built for comfort whether you’re dozing off, fast asleep, or lounging in your tent. Convenient arm openings allow you to adjust the WarmZip without unzipping the side entry. They also let you reach your gear, read, play cards, or even high-five your campmates—all while staying cozy inside your bag. Need to cool down? The armholes provide ventilation, while the two-way side zipper allows for airflow around your torso or feet. Every zipper on the Boost features a durable YKK anti-snag pull, eliminating frustrating snags and ensuring smooth, hassle-free adjustments.

Ultra-Cozy Backpacking Sleeping Bag for Warm Weather with Adjustable Fit and Warmth

• Customizable Comfort: Switch between a roomy semi-rectangular shape or a snug mummy-style fit—adjust the shape and warmth with a simple zip to match your comfort needs.
• WarmZip Technology: Innovative center zipper design reduces internal space and wraps insulation around you, increasing warmth by up to 10°F (6°C).
• Versatile Arm Openings: Easily reach the WarmZip, read, play cards, or ventilate—all while staying comfortably inside your sleeping bag.
• Plush & Insulating: 650-fill, RDS-certified hydrophobic down is strategically placed using Zoned Insulation for optimal heat retention and premium coziness.
• Sustainable Materials: Made with GRS-certified, 100% recycled nylon shell and liner, plus a PFAS-free water-repellent coating for eco-friendly durability.
• Inclusive Sizing: Available in Short, Regular, and Long lengths, with optional Wide widths for a tailored fit.
• Thoughtful Details: Features YKK anti-snag zippers, a cinchable hood, a draft tube along the zipper, a plush draft collar, and a two-way entry zipper for added convenience.

• Fill material 650 Fill Duck PFAS Free Hydrophobic Down, 
• Shell fabric 20D 100% Recycled Nylon Rip Stop 
• Lining fabric 20D 100% Recycled Nylon Rip Stop
• Zipper side Left

Temperature

• Comfort: 5c
• Limit: 0c
• Extreme: -15c

Specifications:

Short:

• Weight: 0.8kg
• Length: 188cm
• Pack Size: 20x17cm

Regular

• Weight: 0.95kg
• Length: 203cm
• Pack Size: 25x17cm

Long

• Weight: 1.1kg
• Length: 216cm
• Pack Size: 28x17cm

UK Postage

To provide the best possible service we use different courier services depending on the item Size, Weight and service selected. The Couriers we use are Royal Mail, Amazon Shipping, DPD & FedEx.
Most deliveries are made per working day [Monday to Friday] and exclude bank holidays, If you feel you will not be in to receive your parcel, please take advantage of using a different delivery address where someone can take delivery. All our couriers have pick up locations and can be selected once you have the tracking number and the courier has the parcel.

Deliveries are made between 8am till 9pm unless a specific option is chosen.

All Express delivery orders must be placed no later than 11am to be posted the same day [Monday to Friday]. Orders placed after this day may be posted the following working day

England, Wales & Southern Scotland
Order Value Up to £74.99
Low value & Large Letter Size - 2-5 Working Day*  - £2.50
Standard Parcel - 2-5 Working Day - £4.00
Express Delivery 1-2 Working Day - £8.00
Before 1PM - 1-2 Working Day - £10.00

Order Value Above £75.00

Standard Parcel - 2-5 Working Day - Free
Express Delivery 1-2 Working Day - £6.00
Before 1PM - 1-2 Working Day - £10.00

• Certain oversized items, or items with an excessive length or diameter, carry a £20 surcharge. This is added during checkout and indicated in the product description.

North Scotland,Scottish Islands, Isle Of Wight

Order Value Up to £74.99 & Under 1.99kg
Low value & Large Letter Size - 2-5 Working Day*  - £2.50
Standard Parcel - 2-5 Working Day - £4.00
Express Delivery - 1-2 Working Day - £8.00

Order Value Above £75.00 & Under 1.99kg
Standard Parcel - 2-5 Working Day - Free
Express Delivery - 1-2 Working Day - £6.00

Order Value Below £74.99 & Weight 2-4.99kg*
Standard Parcel - 2-5 Working Day - £4.00

Order Value Above £75.00 & Weight 2-4.99kg*
Standard Parcel - 2-5 Working Day - Free

Weight 5kg to 15kg - 2-7 Working Day - Flat £20.00 Charge

*This delivery service is restricted depending on Size & Weight of the parcel. If your order is of an excessive size we may have to cancel the order

Channel Islands, Isle of Man, Northern Ireland,

Order Value Up to £74.99 & Under 4.99kg
Low value & Large Letter Size - 2-5 Working Day*  - £2.50
Standard Parcel - 2-5 Working Day - £4.00
Express Delivery - 1-2 Working Day - £8.00* - Under 1.99Kg only

Order Value Above £75.00 & Under 4.99kg
Standard Parcel - 2-5 Working Day - Free
Express Delivery - 1-2 Working Day - £6.00

Weight 2.00 to 2.75kg - 2-7 Working Day - Flat £10.00 Charge
Weight 2.76 to 15kg - 2-7 Working Day - Flat £25.00 Charge

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Can I return an item?

We can accept goods back for exchange or refund or Credit, The goods need to be of re-saleable quality and all labels and relevant paperwork are present. We will not accept any item back that has been worn, or not in a re-saleable condition i.e animal hair's, odors from smoke or fragrances, or any sign that goods have been used other than inspecting indoors.

As it’s the buyer’s responsibility to post goods back, we highly recommend using a courier with the correct insurance and proof of delivery back to us. We cannot be held liable for items lost in post.

Before sending your item back please make sure of the following

• The item is still in a new and unused condition, free of odours and pet hairs
• All labels and swing tags are still attached to the garment, and any boxed items are kept in the original box.
• Any items which are blister packed are still in the condition in which they are sent.
• Tents and canopies have not been erected and still in their original box.
• If your order included a promotional item (such as a free gift or multi-buy offer), all items must be returned in full to qualify for a complete refund; otherwise, the value of any retained items will be deducted from your refund.

Full Returns Information can be found here

Outdoor Action Accept the following methods of Payment

• All Major Credit Cards [excluding American Express]
• Paypal
• Paypal 0% Finance or Split Payment - More info

All payments are made via a super-secure webpage & following GDPR procedures