For use with Stuart® block heaters. Manufactured from anodised aluminium and all with a separate hole to accommodate a thermometer if desired. For accurate thermometer measurements please check your thermometer has a suitable immersion depth. All blocks* have dimensions (w x d x h) of 75 x 95 x 50mm and can be used in any combination. Please note all Stuart® block heaters will only operate effectively if the full compliment of blocks is present.