Reusable Therapy - Oversize terry-filled pack/cover, 24" x 30" Hydrocollator Heating Units - Moist Heat Packs - Oversize terry-filled pack/cover, 24" x 30" Hydrocollator Heating Units Keep Warm Packs Always at Your Fingertips Units run on regular tap water, keeping packs at 168?F and feature sensors to warn of low water level and overheating. Stationary unit is small enough to keep on a counter top; mobile unit is large enough to service a complete department. No plumbing required. Packs included.