Wow, what a brilliant key! At 4.75mm, a snug fit on all my bleed screws. Large physical size of 'wings' give plenty of torque on stiff bleed screws without rounding off the square . I wish that I had had one of these in my toolkit years ago. Many thanks for supplying such a great item. Very fast delivery much appreciated too.

CAST IRON RADIATOR KEY SOLID BRASS PLUMBING BLEED AIR SQUARE KEY 9 SIZES 4 - 6MM (#325546090628)

Good solid brass key not usual alloy. 4.75mm is better fit on standard radiators.

RADIATOR KEY SOLID BRASS PLUMBING BLEED AIR SQUARE KEY 9 SIZES 4 - 6MM (#325546089152)