Recessed mounted is inside a box with 1 side open, have louver then mounted inside the ceiling facing the opening downward. While surface mounted is directly screwed on the ceiling.
That is a recessed screw mount.
The location is will be mounted. Whether is be recessed, or surface mounted. If you plan on ganging boxes or not for multiple switches or receptacles. The amount of wires that will be entering/exiting the box.
PITS
pit
A pit type weighbridge is mounted in a pit. It takes more work to install. The weighing surface is level with the road. A pitless type weighbridge is mounted on the surface. The weighing surface is mounted with a ramp leading up a short distance.
Normally it is mounted on the engine block. The surface is called the oil filter mounting surface.
Surface Mounted Device
The 2008 National Electrical Code (NFPA 70) Article 410.136 (B) requires surface mounted luminaires containing a ballast to be listed for mounting on the fiberboard or they must be mounted not less that 1 1/2 inches from the surface of the fiberboard.
collage
Having same problem with mine, I have read that this is caused by rust on the surface that the rear abs sensors are mounted to. This apparently increases the distance between the sensor and the part on the wheel that the sensor monitors. Advised fix is to clean rust from surface, if this does not work the addition of a thin washer between sensor and the surface it is mounted on may be required to restore the appropriate gap. Will be trying this this weekend. Good luck.
SMD stands for "Suck My D--k"SMD: Surface Mount Device
pi x radius^2