Sourcing a discontinued part
The GJL2811001R8100: If you need a drop-in replacement, the contact rating is 63 A, which is the primary selection parameter. Confirm the coil voltage and contact configuration from your existing unit's nameplate before sourcing an alternate.
What the 63 A rating means for fit
For motor starting (AC-3), the contactor's make/break capacity is lower — typically around 30–40 A for a 63 A frame — because the inrush current and inductive break stress the contacts harder. If this contactor is switching a motor, verify the motor FLA against the AC-3 rating of the frame.