The local Walgreen's has switched over to then ATX and thus they now only carry the HB4 blades. Tue label says it is for all models of headblade. As I needed a blade in bought a pack.
I'll be calling the 800 number for an adjustment. The experience was awful. Felt like I was shoveling rock. Snags all over the head. Certainly not smooth. I've never had a shave so rough in all my months of shaving my head. Knowing Headblade, they will treat me well. I'm sticking with the HB3 blades.