Good catch, inspectorD. I forgot that, as my orbital disappeared (jumped or walked off), and have been using my oldie piece of Black and Decker. Some new ones have settings of degree of forward movement, and even a light, which is really cool! The most fun is having to use your skill saw and hole saw---very carefully---when cutting out.
I installed 8 mill plastic sheetrock dust guard about 12" x 12", between jig and shoe base, to cut ceilings. Use a regular blade, shortened (2 pliers snap) to 5/8 long on the down-stroke. It barely scores the ceiling joists and never cut pipes or wires when demoing. Be safe, GBR