RT-4C11ATX or 4C11SR
Dimensions: 483(W) x 177(H) x 427(D)mm
(19" x 7.0" x 16.8")
Drivebays: 2 x 5.25", 1 x 3.5" Open, 1 x 3.5" Hidden

RT-4C13ATXR/SR
Dimensions: 483(W) x 177(H) x 451(D) mm
(19” x 7” x 17.8”)

Drivebays: 3x5.25" + 1x3.5"FDD at bottom opening.

RT-4C21ATXR/SR
Dimensions: 480(W) x 177H) x 510(D) mm
(19” x 7” x 20.1”)

Drivebays: 3x5.25" + 1x3.5"FDD at top open, Optional 1x3.5"HDD hidden.

RT-4C22ATXR/SR
Dimensions: 480(W) x 177H) x 510(D) mm
(19” x 7” x 20.1”)

Drivebays: 4 x 5.25" + 1 x 3.5"FDD open, Optional 1 x 3.5"HDD hidden. 

RT-4C25ATXR/SR
Dimensions:

480(W) x 177H) x 510(D) mm
(19” x 7” x 20.1”)

Drivebays: 3x5.25" + 1x3.5"FDD open, Optional 1x3.5"HDD hidden.

RT-4C27ATXR/SR
Dimensions:

480(W) x 177H) x 510(D) mm
(19” x 7” x 20.1”)

Drivebays: 3x5.25" + 1x3.5"FDD open, Optional 1x3.5"HDD hidden.