Sigma Thermostatic Extension Set 18.30.216
Sigma Thermostatic Extension Set (2-3/8" Threaded Tube and 3" Square Tube) 18.12.069
Sigma Thermostatic Extension Set 18.30.217
Sigma Thermostatic Extension Set (1-1/2" Threaded Tube and 2-1/4" Square Tube) 18.12.060