J-50 Series
The J-50 slip top box series holds 50 rounds, features a non-see-thru material and has round holes. Since the holes are round, they are used as a reloading block with an advantage of having a cover.
FITS:
.38 Spec., .357 MAG

Length (inches)	9.88
Width (inches)	8.75
Depth (inches)	5.5