The Terma 43D element is pre-programmed to run at an internal temp of 43°c, for Low Surface Temp (LST) style operation* When specifying this element, to help ensure correct surface temp, reduce the output of your radiator (as water) by 40% (i.e. for a 200w towel rail install the 120w element). No Timer. 2hr drying function. Compatible with external Timer as remembers settings when off. 66mm length from thread down. 55mm diameter clock shaped face. Frost & overheating protection. Straight cable, no plug. IPx5 (safe for use in bathroom). Class 1.