Based on this product's specifications, here are some alternatives and similar models
Magnetic Reed Sensor SATEL B-2 — cylindrical surface-mounted contact for security systems
Summary description:
SATEL B-2 is a cylindrical magnetic reed contact designed for surface mounting in security and alarm systems. The device provides door/window open/close detection via a magnetically actuated switch in a compact cylindrical housing. It is intended for reliable zone monitoring in residential and commercial intrusion detection applications where a discrete surface-mounted contact is required.