This is Strathearn's SP100 Concentric Millefiori weight. In 1979 Strathearn came out with three new paperweight series, the SP series (which was the basic design for the other two series), the PPS series and the PSFS series. Each of the three newly introduced series had three new pwt designs designated as 100, 101 and 102. The three basic designs used were the concentric millefiori which is shown in this album, the patterned millefiori which can be seen in the SP101 album and the garland millefiori which can be seen in the SP102 album. The Strathearn Trade brochure states of these new pwts..."Our new range of paperweights of millefiori designs to be limited to 500 pieces in each design and style. Each weight will be signed, numbered and authenticated and supplied in a special horseshoe shaped presentation box". As with almost all of the special faceted and multi-faceted and collectors range of pwts Strathearn did not always sign, date and number each and every weight, some weights...yes, some weights...partially and on others only on the authentication card. The Trade brochure copy that I have is not dated so I do not know exactly when in 1979 these were first introduced but they were carried on into 1980 as I have some dated 1980 and have seen others.