Hydrapak Seeker 4L Hydration pack

Amazon

PORTABLE & PACKABLE: Crush the Seeker Hydration Reservoir when empty and store in the included storage bag. The flexible design makes it so light and compact, you'll forget it's in your pack. DURABLE & VERSATILE: Made of flexible and abrasive-resistant TPU, the Seeker can be frozen to use as an ice pack, filled with hot water (max temp 60°C/140°F), or kept in your camp kit as your go-to filter bag. EASY TO USE: Low-profile, weather resistant handle and load-bearing lashpoints make this hydration reservoir easy to handle, pour, and carry; the large 42mm opening makes it easy to fill. WATER FILTER COMPATIBLE: Filter more water in the backcountry, most 42mm threaded filters, including HydraPak's 42mm Filter Cap. LIFETIME WARRANTY: Beyond Lifetime Guarantee covers all reservoirs from manufacturing defects in materials and workmanship for the lifetime of the product.

Snowcountry

Go the distance with the high-capacity Hydrapak Seeker 4 L. The flexible coated handle allows for easy pouring and carrying. It packs away nice and easy. Its streamlined shape fits in a wide variety of packs, whether strapped to the outside or inside a pack pocket. Pairing volume with performance. The large 42mm opening makes the water bag easy to fill and it is also water filter compatible, giving you the option to filter water.