Delta 551-DST Features: Why Buy Delta Dryden 551-DST Bathroom Faucet From Us: Delta 551-DST Technologies: DIAMOND™ Seal Technology: Delta® DIAMOND Seal Technology utilizes a ceramic disc valve with a real diamond coating to produce a faucet that will last up to five million uses. That's twice as long as the industry standard, guaranteeing a lifetime of leak-free, trouble-free performance. Delta Innoflex PEX supply lines are included with DIAMOND Seal faucets, so everything you need is in one box. Delta 551-DST Specifications: Variations: