All red slots are boiler red. A1 is a double, A2 and A3 are triples. Kavats are sold by the pair of imprints. (Only one pair of A3 remaining) Get 2 prints of A2 and 2 prints of A3 (make your own solid kit) for 300p. Happy to discuss any other bundle deals! Image of an A2xA3 solid under the read more.