Reusable Therapy - 15 1/2"W x 26 3/4"L x 33"H Hydrocollator HotPac & Units - M2 Mobile Unit - 15 1/2"W x 26 3/4"L x 33"H Intermediate size with extra-large tank; includes 12 standard size HotPacs. Hydrocollator HotPac Introduces Improved Moist Heat Technology with New, Synthetic Fabric Here's an easy way to provide moist heat therapy for patients-quickly, easily and targeted to any point of the body. HotPacs provide up to 30 minutes of moist heat per session. And now, they have a new synthetic covering that helps resist mold and mildew, dramatically increasing their lifespan. You'll get hundreds of treatments from each pack.