The GM22 Clam Shell with viewing window runs on 240v - requires 31 amp breaker. Inside dimensions 24" x 25" x 13.5" deep, 4.35 cubic feet. Glassmaster conroller gives you GlassFire Mode allowing you to write a program simply by choosing your technique and the speed. Write your own firing programs with up to 8 Segments using Ramp and Hold. Now you can store up to 8 programs. Adjust temperatures or hold times while the kiln is firing using Add Time or Add Temp or simply select Anneal Now to set your project and begin annealing it. Fires to 1800 degrees fahrenheit. Viewing window mounted on side for perfect viewing is made of quartz to withstand the temps. Instruction manual, and warranty card included. Two-year warranty.