I have three of the original Headblade push-style shavers I've been using for 18 years! I keep one in my travel bag and the other two in different bathrooms in the house. Early on, I'd often accidentally cut myself with the HB2 blades if everything wasn't just right (wetness, cream amount, blade angle, etc.) Was very excited when the HB3 blades came out as the 3-blade design virtually eliminated accidental cuts, but was bummed when HB3 blades were discontinued. After I used my last HB3 blade, I reluctantly resorted to using a disposable razor. After about 6 months of that I realized the HB4 blades and adapters (meant for pull-style Headblade shavers) could be used on my original push-style shaver! What a god-send because I don't like the shave I get with the pull-style Headblade shaver! I once again am using all my Headblades! I am a happy camper and am stocked-up on enough HB4 blades, adapters and cream to last a couple years. Thank you!