There's now an easier way to smoke your concentrates. The Colour Blocked Bubble Cap from GEAR Premium® is made of 100% borosilicate glass and has an easy-to-use ergonomic design to maximize air flow and get the most out of each hit. There's now an easier way to smoke your concentrates. The Colour Blocked Bubble Cap from GEAR Premium® is made of 100% borosilicate glass and has an easy-to-use ergonomic design to maximize air flow and get the most out of each hit.