Medium Duty Wire Nut Fastened: The series MWNF has a wide grip range (total thickness G up to 15 mm) This series is suitable for a large range of application. MWNF is very easy to install with his single-hole mounting. 3 kinds of head style. STUDS: MWNFTLS Medium Duty Wire Nut Fastened Turnlock Slotted Recess Head This is the Slotted Recess Head version of the MWNFTLS-series. The Slotted Recess Head version is only available in steel zinc plated. Spring is in stainless steel. MWNFTLSW Medium Duty Wire Nut Fastened Turnlock Slotted Recess Head with Decorative Washer This is the Slotted Recess Head version of the MWNFTLSW-series. The Slotted Recess Head version with decorative washer is only available in steel zinc plated. Spring is in stainless steel. MWNFTLW Medium duty Wire Nut Fastened TurnLock Wing Head This is the Wing Head version of the MWNFTLW-series. The Wing Head version is only available in steel zinc plated. Spring is in stainless steel.