Inlays V623500 FT AB Series Non-Skid Vinyl Stick-On Depth Marker with Centered 4" Black Lettering on White Sticker, Radius Corners. The Inlays V623500 is a 6" x 6" AB Series Non-Skid Vinyl Stick-On Depth Marker with a centered "FT" in 4" black lettering on white sticker with radius corners. The depth marker helps to create a safe swimming experience for everyone, and is used to mark where it is safe to dive and how deep the water is. Enjoy these vibrant and bold depth markers for any swimming situation.