The red one is ok to use without thimbles. The silver square case (has a 6 digit serial number) is also ok. I think you can use the round case (5 digit serial number) but double check with your regional secretary. I word of warning rubbers have been known to ride round on the inner carriage pulling them out of the box chambers and invalidating the pigeon.
Club issued to 25201– 25800 NW50 KERSAL VALE H S Mr K Whittle, St Clements Vicarage, 35 Hulton Street, Ordsall, Salford, Manchester M5 3WQ. Tel: 07748 414687
Think it all depends what you set your stall out for. 90% of our fed program is what I would call sprint racing, any yearling showing promise in these races dont go past the 200 mile mark.