Annis Han-D-Mags are available in 8 different models. The more usual, standard Model 115-S, short probe model has a 2 1/4" long probe that is .415" thick. Long probe models have a 4 1/4" long probe. Thin probe models are only .315" thick Efficient magnetic design of the Han-D-Mag has resulted in a 5 times more efficient Head Demagnetizer.