SW09 – MERKEL HELIX – SABATTI SAPHIRE – SAKO S20 DOVETAIL RAIL Dovetail rail 12 mm 60° for MERKEL HELIX – SABATTI SAPHIRE – SAKO S20. Contessa dovetail rails in hardened steel are machined from solid, designed to guarantee stability and long-term resistance. Screws and a wrench for mounting are supplied.