The OMS bag for (harness 5.0cm) or narrower has a small compartment with a zipper on the outside and two bungees on the inside to which equipment parts can be attached. There is a strap for the harness on the back of the bag.
 
 Details:
 
 Dimensions: 30cm high, 21cm wide
 Outside zip
 2 inner compartments (large and small)
 Bungess for attaching diving accessories