This is a charcoal stove for curing purposes. Use 2 rentans up and down 2 rows for 15 to 17 hours. Rentan can be used with one match rentans or Newchukka. Size: Height 13.4 inches (340 mm) x Width 6.7 inches (170 mm); Cement usually begins to cure in about 4 hours, but it must be avoided by water freezing, especially in winter. Curing stove prevents water from freezing and makes concrete curing easier. Please do not use this curing stove for purposes other than concrete curing. Please be careful when using carbon monoxide poisoning.