Found 4 alternatives for PTA50010 by Celduc. Magnetic Sensors Position Proximity Speed Modules — Cylinder, Wire Leads.
BLUE 140VAC/0.5A TUBULAR PROXIMI
BLACK MOULDED 140VAC/0.5A PROXIM
PROX SEN 53071820 1NF/60W/400VAC
PROXIMITY SENSOR 1NO/2 WIRES WIT