I have the razor that these refills belong to. I can tell you that one box of these re- fills lasts me almost an entire year. The blade is so sharp on these it is amazing. These blades can even get a close shave when they are dull. Even after the moisturizing strip in the blade runs out. Just throw on a little shave gel and you are good to go. I have been using this same razor and refills since it first came. They aren't to expensive especially since there are always coupons coupons coming out for these. If you have tried this you need to try it. These are my favorite refills for many reasons. The number one reason being that they have 4 blades on them. I prefer not to shave with any less than that. I have no issues using the four blades and they make my skin feel incredibly smooth with how close the shave it. To be honest, it is very hard to cut yourself with these blades. I never have. You do not need to apply a lot of pressure at all either. Just a light once over on whatever area you are shaving and that is it!