This is the Wilton's Cake Leveler that I bought ((below $10) from Phoon Huat. I used it mainly to help me cut the cakes horizontally before sandwiching them with cream. The stainless steel string is adjustable in height. There are markings on the 'legs' so that you can adjust the string accordingly. I find that cutting the cake is a breeze using this simple tool. Just place the cake on a leveled surface and place the leveler on the table and guide the tool and hence the string through the cake to get a straight & even cut. Minimal crumbs, especially if you allow the cake to chill in the fridge first. I've also discovered a new use for this- cutting up cheesecakes!
Wilton's Cake Leveler Tool
Markings on the legs to adjust the height of the string