Solid shaft of Model BSM measures 4 mm dia, but also mates with 2 mm dia shaft via hollow tip. Hollow shaft of Model BHM mates with shafts 1.5-3 mm dia. Both measure angle, rpm, or rotational direction with resolution of 2,000 steps/rev, and tolerate -20 to +85°C. Axial socket connector grants access to A, B, and N outputs, each of which enjoys short-circuit protection.