Brand No Model HC-020K Quantity 2 Color Green + black Material FR4 Features Wide voltage high resolution short response time switch output; Can test motor's rotational speed w/ black encoder (measured spec. is related to the encoder the inner diameter of D type encoder that provided is 4mm can be used for motro output shaft w/ 4mm diameter which is TT motor we matched yellow shell and white axis Specification Working voltage: 4.5~5.5V; Launch tube pressure drop: Vf=1.6V; Launch tube current: If Application For experiment English Manual/Spec Yes Packing List 2 x Encoders 2 x Module 1 x Chinese / English user manual