Just to mention, in case I'm the only one who took a while to realise it, the Merkur Progress adjustable has an indentation on the removeable head which must be aligned to the indent on the base handle unit. If the head is mounted the wrong end round it really does knock out the adjustment. Mr. Merkur neglected to mention this in the wrapping when I bought the razor and, being on the slow side it was a wee while before I cottoned on.