I culled some spare porcelain pin bases from my collection . All three of these are 1902-04 production and have good clear Fred M.Locke markings.... Left to right in the photo.... Brown glaze 2 7/8"wide, 2 1/2" high, some small micro nicks, this base would be used with 1 3/8 threaded insulators like the U-529a with a short inner skirt. These are very scarce!! ------ White unglazed base, W-2 5/8"x H- 2 1/8" ,small flat chip on the base (see second photo) this base would have been used with white glazed versions of insulators like the U-447 or similar sized glass insulators like the Locke#15 or Locke#20 with a 1"thread,------- White unglazed base, 2 5/8 wide, 3" high. This base was used with the CD 288 Locke #18, Locke #16 or other long skirted white porcelain insulators with a 1" thread . This is also a scarce base