The RIVOTEK heating mantles are manufactured with heating surface which are resilient and can hug the flasks to take several size or multi size flasks in the same mantle as indicated in the table below. The size of 10 litres has two heating circuits and the size of 20 ltrs have 3 heating circuits. When heating a small flask or when the contents of the flask are low, the upper heating circuits can be switched off by a switch or switches provided on the outer metal case.