This pack counts 10 universal double edge blades made of stainless steel. We advise to replace your blade every 5-10 shaves. This can vary from one person to another depending on multiple factors (hair thickness, area shaved, skin sensitivity, etc). A good rule of thumb is to change it when you find the shave to be less close than the first time, or if you start having irritations caused by a dull blade.Dimensions: app 4.4 x 2.5 cm