Here are the specifications for the standard budgerigar show cage.

Timber: 8 mm
Size: Overall measurements – Length 355 mm, Height 305 mm, Width 165 mm.
Top: Length 355 mm, Width 140 mm, with 75 mm x 25 mm Kidney shaped Hand hole in Center.
Bottom: Length 355 mm, Width 165 mm, May be nailed or screwed.
Ends: Height 289 mm, Width 165 mm, with top front corner rounded to a 19 mm radius curve.
Door: Door opening 105 mm high x 76 mm wide in centre of right hand end. Door hinges at the top with two 25 mm hinges and fastened at center of bottom edge with neat turn button. Bottom edge may be bevelled or rebated if desired. Doors shall be rectangular.
Back: Height 241 mm x width 355 mm from 3 mm hardboard or plywood nailed from the outside.
Front Rail: Length 339 mm, width 51 mm. Fixed between the ends with a groove approximately 6 mm from the top and running the full length of the rail.
False Roof: Length 339 mm. Fixed 222 mm From inside of cage bottom to inside corner of false roof Front edge set back 38 mm from front edge of ends.
Wire Fronts: To be Chrome Plated Comprised of 21 wires 14 gauge spaced at 15.8 mm(5/8”) centres. Cross bar set 133 mm overall from the outside bottom of the cage. Set double punch bar at top 13 mm apart for strengthening and leave three wires top and bottom as spikes for fixing. Curve to 19 mm radius bow at the top. Punch bar only to be used throughout.

Perches: Length 165 mm overall, cut from 15 mm plain unpainted doweling square cut at both ends, pined or screwed at the rear and cross grooved at the front to firmly grip the cage wires. The perches should not extend beyond the front of the punch bar. Position of fixing screws or pin holes in the back of the cage to be 133 mm from the bottom overall and 127 mm apart, to centre on the punch bar and the seventh vertical wire from each end.

Drinkers: The standard clear round drinker, available from the Society, is to be attached to the inside of the cage between the third and fourth wire from the door end, immediately above the cross bar. Drinkers to be filled at benching. No other types of drinkers are permitted on cages until after judging is completed.

General: Inside to be finished in white Hi Gloss enamel paint or two pot Marine. Outside and top of the front rail with Black HI Gloss enamel paint as described for the inside. Only the perches should be visible inside the cage. No name or distinguishing mark to be visible from the front.