Designed for continuous use on large floors, the Edger Trowel PB24 includes a guard rail edging feature for troweling closer to walls (up to 1/4 in.). Includes a Centi-safety (Dead Man Switch ...
This is typically done with a margin trowel: hold the trowel along the edge and open it up, then start using your edger. This training is one of the basic lessons the OPCMIA teaches apprentices.