Description: You can adjust front 3 gear + rear 7 gear,namely 21 speed or other feasible combination. 7 adjustable gears for 21 speed bicycle. Aluminum alloy cable materials products. Efficiently make you ride the bicycle more comfortable. Can be applied for some ordinary bicycle,mountain bike,folding bicycle,road cycle Specification: Product Name: Trigger shifter Material:Alloy + Plastic Color:Black(As shown in the picture) Fit handlebar: 22.2 mm Model: TX 30 ComponentsTrigger shifter Gear:21 Speed Occasion:Bicycle,bike Quantity: 1 pair Packaging includes: A Pair of Trigger shifter Warm prompt: 1.As different measuring methods,it will occur 1-3 cm deviation about the items,please ensure that it is okay for you before ordering; 2.Because of different monitors and lamplight,the picture may not reflect the actual color of the item,really thank you for your kind understanding! 3.This trigger shifter apply for almost standard mountain,folding bike,maybe not suitable for other special bicycles. 4.Trigger shifter only,other accessories irrelevant demo in the picture are not included.