Had to buy this as the standard Arcadia ones wouldn't fit my Arcadia 100w halogen and I have to say it fits perfectly. The cage itself doesn't open from the bottom like most others and instead you insert and remove it from a lip in the top plate that affixes to the viv.
The only downside to this for me is the top plate the bulb fits through. As I like to use ceramic holders with brackets, I've had to cut away some of the metal to make a square hole so I can fit it around my fittings (This is probably more suited for those who have made holes in the top of their vivs to put the bulb through). I would have preferred if this was more of an open top cage with small holes attached to the rim for the screws instead. Even so, it still does the job it's designed to do.