single-WALL - Stainless steel insulated protein shaker with storage box. LEAKFREE/ SHATTERPROOF - It is proven that a twist-on cap is at least two times more secure than a flip-top cap against spilling and leaking and the lid wont burst open when dropped. No more accidental leaking/spilling leaving a mess and ruining your day. Our exclusive twist-on cap can be used for hot beverages because the inside air pressure can be released/ gas off through the sides of the twist-on cap while opening it slowly whereas flip-top cant withhold shaking hot drinks. YOU ARE REQUESTED TO TIGHT CAP LITTLE MORE FOR NO LEAKAGE COMPLAINT. ODOR RESISTANT/ EASY TO CLEAN - Our premium stainless steel does not absorb odor and is easy to clean without leaving any stains and it wONT rust. The last thing you want to have is smelly stinking shaker. These reusable stainless steel shaker bottles are great for hiking, biking, the gym, travel, school, work, and just about anywhere you might get thirsty!