The Sparrowhawk 1 (S-1) utilizes a single speed drive and  a simple ON/OFF design.  The Sparrowhawk 1V (S-1V) comes standard with a variable speed controller which allows for infinite adjustment of the mop speed to achieve optimum purity of the recovered product.  The S-1 and S-1V are supplied with 5' and 10' of BM-2 respectively but other lengths can be requested.