From Bra Maker's Supply:
The ever-so-popular Ruby bra pattern has a little sister. Introducing the Sapphire partial Band Bra Pattern. The Sapphire must be used with underwires as this is part of the engineering of this lovely bra. Like the Ruby, this pattern features an off-set vertical seamed cup for the roundest styling, and a shortened upper cup for maximum lift. Our testers were amazed at the push-up look this pattern gives. The Sapphire Partial Band Bra Pattern has been specially designed to use with foam lining, therefore enabling you to use virtually any stretch fabric over it as a cup cover. It can even be made without foam, using low-stretch fabrics or fabrics lined with Sheer Cup Lining.
The sizing for the Sapphire is a bit different from other bra patterns, in that we use the Bottom Cup Depth (BCD) to determine the size of the cup. This is the measurement from the wire line at the base of the cup up to the location of the apex. It is much more accurate than relying on Ready-to-wear bra sizing, which can differ from company to company. Determine your BCD by measuring your best fitting bra between these two points. All cup sizes from 3.0 to 6.0 are included in the pattern. Combine these 13 cup depths with 1 of 8 band sizes from 26″ (65 cm) through 40″ (100 cm) to make the Ruby Full Band Bra Pattern size range equivalent to over 100 unique bra sizes.