"Nathan® 1.8L Replacement Bladder: When your hydration pack bladder starts to show wear, the Nathan® 1.8L Replacement Bladder keeps you fueled during training runs, long distances, and race day without skipping a beat. This unisex replacement bladder holds 51-75 ounces of water and integrates seamlessly with Nathan® Race Vests, making it an easy swap when your original bladder needs refreshing. The BPA-free construction ensures safe hydration, while the high-flow bite valve delivers water quickly so you can stay hydrated without breaking stride.The large, easy-fill opening makes it simple to add water, ice, or electrolyte mix before heading out, and the quick-release hose disconnects easily for faster cleaning and quicker setup with your vest. The durable design withstands repeated use across multiple training sessions, so you get reliable performance whether you're logging everyday miles, tempo work, or hydration-focused training. If you already own a Nathan® Race Vest and need a dependable replacement, this bladder delivers the same reliable hydration access you're used to.Why Our Fit Experts Love It""I swapped in this replacement bladder for a half-marathon training cycle and appreciated how quickly it filled and how the bite valve delivered water without any leaking during my runs. The quick-release hose made cleaning between workouts effortless, which kept me hydrating consistently throughout my training block."" - Sean, Road Runner Sports Fit Expert, Chula Vista, CAWho It's Best ForThe Nathan® 1.8L Replacement Bladder is best for runners and athletes who already use Nathan® Race Vests and need a replacement hydration bladder for daily training, long runs, and race day. It works well for anyone seeking a BPA-free, reliable hydration solution that requires minimal maintenance and integrates with existing Nathan® gear. VIP Family members can take the 1.8L Replacement Bladder for a 90-Day test drive with our Perfect Fit Guarantee."