Mashraba is one of Dahab's easy south-side house reefs, reached from the gravel wash near the dive shacks. It is less famous than the Blue Hole or the Canyon, but that is part of the appeal: you can get in the water without making a full expedition of it.
The reef is best for divers and snorkellers already based in Dahab who want a low-key local site. Conditions still matter, so go with a dive centre or someone who knows the entry points.