The Italian company ELTRA produces encoders Incremental & Absolute of all types: With shaft, hollow shaft, axial, and special types for special applications.
The main difference between an incremental and an absolute encoder is how they determine the position.
An incremental encoder determines the position from zero index, whereas an absolute encoder bases its position inside the turn.
Consequently, an absolute encoder does not lose the real position if the power goes out or in case of shifting, and as soon as the power is restored the position is updated and immediately available.
On the other hand, with an incremental encoder the zero set would be required.
Shaft encoders: Ø30, Ø38, Ø40, Ø58, Ø63, Ø90 with axis from Ø4 to Ø11
Hollow Shaft encoders: Ø36, Ø38, Ø40, Ø48, Ø49, Ø50, Ø53, Ø58, Ø63, Ø72, Ø80, Ø88, Ø120, Ø150
Single turn absolute: Ø40, Ø50, Ø58, Ø63, Ø90A, Ø115A
Multi turn absolute: Ø58, Ø63, Ø90, Ø115 parallel SS1 & Profibus