1 hour ago, goncall said:

old racal didnt they use to have a strange 2 wire thing pos alarm and neg tamper 

 

dunno, but its one of these-

 

 

 

 

 

 

"Now With Extra Features!"

 

* Detects movement!

* Tamper now works 3/4 times

* Only uses 600mA

1 hour ago, MrHappy said:

 

dunno, but its one of these-

 

 

 

 

 

 

Hardcore , always force that screw out once it's been in for years 

9 hours ago, MrHappy said:

 

dunno, but its one of these-

 

 

 

 

 

 

When used with an old racal panel,quite common back in the day

An acquisition in my area used thousands of the things.