Typically 240V for home and studio. Some schools require 208V. - 18" tall model has 2 rings and is approximately 2.8 cubic feet. The 23" tall model has 3 rings, or approximately 3.5 cubic feet - 8 sided kiln, fits any 15" octagon shelf. - Requires a minimum 30 Amp breaker - Made with 3 inch fire brick - Usually ships in 2 weeks or less, special orders will increase lead time. - Ships freight, on a pallet Our top selling kiln models are: 18" diameter, 23" diameter, and 28" diameter. Made in Seattle, WA, USA since 1975. ETL certified, 1 yr warranty