After reading reviews here and on other sites I have decided that I want to buy my husband a Merkur HD safety razor for father's day. When I looked it up on Amazon.com I found a few varieties and I am not sure which razor to buy. I found a Merkur HD 34C, Merkur Model 38 Hd Classic "Barber Pole" Long Safety Razor, Merkur "Heavy Classic" Double-Edged Safety Razor 34c, and Merkur HD Slant Safety Razor 37C. What is the difference between these razors? Thanks in advance for any advice you can give me.