Data sheets give drawings and dimensions of bases, caps and associated gauges and pin straightening tools for those electronic tubes registered in the United Kingdom.Cross References:BS 308BS 427:Part 1BS 448:Part 1BS 1407Replaces BS 448:Part 1:1953, BS 448:Part 2:1953, BS 448:Part 2:Supplement No. 1:1966, BS 448:Part 2:Supplement No. 2:1968, BS 448:Part 2:Supplement No. 3:1971 and BS 448:Part 2:Supplement No. 4:1973.