EUROCARD is a developed industry mechanical standard, setting out a standardised format of dimensions for both rack cards, sub racks and 19″ rack frames.
The Eurocard standard has become widely adopted in Engineering Design and Research & Development fields – it is a mechanical standard and a little like the old Meccano system of years gone by, having a wide range of accessory choices which can be mixed/matched to create the required configuration within a 19″ rack system.

When a rack sub-frame is fully populated you can easily end up with masses of connecting cables/leads coming from the rear of the sub-frame and this is where the frame support rails come in very handy.
This cable support rail simply screws into the existing sub-frame and you can then easily arrange your cabling tidily and either lace it or as is more common these days, just use a plastic cable lock to hold everything in place.

The support rail is metal (steel/ferrous)
Length is 420mm
Mounting hole at each end, these are spaced 400mm apart
Hole is 4mm diameter
When mounted on the rear of a sub-frame, the rail adds a further 27mm to the overall depth of the sub-frame
Weight: 100g

To mount these, just use the normal rack bolts (with a washer) or if you don’t have any, I can probably find a couple of bolts to suit around here somewhere!