https://www.asmag.com/project/resource/index.aspx?aid=16&t=secutech-made-in-taiwan-products-and-solutions
Product Info
Gianni Industrial GD840SC Electromagnetic Door Holder

Gianni Industrial GD840SC Electromagnetic Door Holder

GIANNI INDUSTRIES INC.
Region: Taiwan
Update: 11/10/2015
Key Specifications

Features:
• Wall Surface Mount. 
• Operating Voltage: 24VDC (12VDC is available by special order). 
• Current Draw: 60mA / 24VDC. 
• Push-off Button: Push to cutoff the power and then the magnetic door holder is inactive. 
• LED Indicator: It’s lighted and visible especially at night time to enhance safety. 
• Holding Force: Up to 80 lbs. 
• Anti-Residual Magnetism Function.

https://www.asmag.com/project/resource/index.aspx?aid=16&t=secutech-made-in-taiwan-products-and-solutions