The SkinSafe™ trimmer blade for The Lawn Mower® 5.0 Ultra is rounded for comfort with a built-in metal guard for a smooth glide. SkinSafe™ technology* doubles down on comfort with a built-in metal guard that acts like a comb. Thoughtfully designed at a precise distance from the guard to help reduce nicks and cuts. *Note: SkinSafe™ technology does not guarantee cut protection.