Hydrocollator Heating Units remain the benchmark against which all others are judged. Durable and easy to maintain, these high quality stainless steel units provide a constant supply of temperature consistent HotPacs. Model M-2 Heating Unit Complete with 12 Standard Size 10" x 12" (25cm x 30cm) HotPacs. Our most popular intermediate-size unit. Hydrocollator Heating Units feature: • Extra large tank. • Includes 12 Standard Size HotPacs. Supplied ready for immediate use and requiring no special plumbing • Fiberglass insulation for reducing heat loss and maximizing energy efficiency (except for the E-1 and E-2 Heating Units). • Easy to maintain. Simple to fill and drain. No plumbing required. • 3" (7.5 cm) swivel-type rubber casters for silent, friction-free movement of mobile units. • UL listed, CSA certified.