Shabbat Gramma systems (SGS)

Our products provide access control solutions that are permitted on Shabbat without any limitations!

DeltrexUSA has designed and developed security systems for entrance to apartment buildings, synagogues, yeshivas, hospitals and security installations to be used by Shabbat observers. Using the principle of GRAMMA (indirect action) and the method of “modified current” (SGS), our systems are authorized to be used on Shabbat without any limitations.

SGS does not open or close an electric circuit.

The halachic approval for this action is based on the fact that the prohibition of using electricity on Shabbat is to open or close a circuit (this is a violation of the action of Boneh – construction – or Molid – "giving birth" to something new). But modifying a property setting (current, voltage, frequency, or capacitance) of an existing current is permitted.

This technique is suitable for doors that are operated through the use of a magnetic lock, electric lock or electric strike.

A touch type switch is used as a sensor that changes the voltage, current, and the frequency because of the electronic proprieties of the human body. It can sense and respond to the slightest human touch replacing the mechanical switch applications. The variation in changes also depends on how long the hand maintains contact with the surface.

The Shabbat Gramma Systems (SGS) have been approved by the most prominent rabbis and they are routinely used in many places where religious people regularly pass through. 

Certificate of compliance is available on request. 

For additional information on our Shabbat Gramma System, Please email us at or give us a call at 718-401-4006