Amerimax's Metal Lock-In Gutter Guards can be used on 4 in., 5 in. and 6 in. "K" style gutters. The pre-notched design allows for overlapping which eliminates gaps between the guards. The gutter guards are easy to install - just slide the flat side under the shingle and lock the curved portion into the front edge of the gutter. This product is designed to handle high volume rainwater flow via its wire screen and hold up to the heat and cold better than vinyl gutter guards.