what are dimensions?
For the SK716, the dimensions of the middle (main/thick) part are
17 5/8" L x 12 3/4" W x 2 3/8 Thick.
The dimensions of the top part are
17 5/16" L X 12 1/4" W (the thickness varies due to its egg carton shape).
The replacement foam insert is 21" by 15" and 10" deep. There are 7 layers of foam of different thicknesses to total 10" (the thickest being 1.75". Some layers are cut to fit around wheel indents in case.
Insert for lower case compartment consists of two layers, each 16 ?? x 9 ?? x 2? thick. Tear-out pieces are 5/8? x 5/8? and 2? deep. Insert for case lid is an egg crate type cut, 1 ?? max. depth. The insert kit fits well into the case. I use my case to store and carry telescope eyepieces and am comfortable with the level of protection provided.
I would have to get the actual dimensions at home and send them to you later. However, according to Underwater Kinetics web site for the 716 UltraCase, the internal dimensions are (L W D) 16.90 in x 9.90 in x 6.50 in / 42.93 cm x 25.15 cm x 16.51 cm. The foam kit fits into the case very nicely.