Incremental Optical encoders are available with solid or hollow shafts.

Encoder	Shaft type	Shaft sizes	Output	Protection
IH100	hollow	24 mm 25 mm 28 mm 38 mm 42 mm	PP (push-pull) OP (push-pull, inverted) LD (line driver, 5 V) LD24 (line driver, 24 V)	IP65
IH58	hollow	6 mm 8 mm 10 mm 12 mm 14 mm 15 mm	PP (push-pull) OP (push-pull, inverted) LD (line driver, 5 V) LD24 (line driver, 24 V)	IP40 IP66
IV36	solid	4 mm 6 mm	OP (push-pull, inverted) LD (line driver, 5 V) LD24 (line driver, 24 V)	IP65
IV58	solid	6 mm 10 mm	PP (push-pull) OP (push-pull, inverted) LD (line driver, 5 V) LD24 (line driver, 24 V)	IP65 IP66
IV58L	solid	6 mm 10 mm	PP (push-pull)	IP64