200V, 0.5A Mini Reed Switch by Aleph America Corporation (HYR-1532).

Specs:

Size of glass body (excluding leads) 14mm lengths x 2mm diameter

Normally open until you apply a magnetic field to it.

Warning:

This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov