This is an emergency switch used essentially for emergency stop of machines and industrial applications. Just push the red cap to engage, then twist to release.

Features

• Current/voltage rating: 3A-250VAC
• Electrical function: push to shut off, twist to release
• Mechanical life: 10000 cycles
• Operating Temperature: -25℃~+85℃
• Material: Plastic and Metal
• Button Diameter: 23.4mm
• Size : 45 x 23.4mm (L*D)
• Mounting Hole Dimensions: 16mm 

Emergency stop switch datasheet