Rugged, diecast aluminum alloy (tough yet easy to machine), electronic instrument enclosure. Lid screws are exposed for easy enclosure access (if you require higher security see our watertight flanged lid version). Bottom flange is an aluminum (type 5052 H32) plate, spot welded onto the base of the enclosure. Lap joint construction with a factory poured silicone rubber gasket around the perimeter of the lid provides protection against access of dust and water. NOTE: we have made a “running change” improvement to this series – after August, 2010 production. Units made after August 2010 will have a separate – self adhesive silicone gasket included. Silicone rubber gasket remains flexible from -62 to +232ºC (-80 to +450 ºF). Unpainted version is vibra finished for a smooth surface with no sharp edges. Painted version is painted with tough – satin black polyester powder paint for a lasting finish, even after machining. Black stainless steel screws are included to enhance assembled appearance. Quantity four (4) 6-32 x 1/2” stainless steel, machine screws secure lid (or six (6) in 1590WDF, 1590WDDF, 1590WEF & 1590WR1F or eight (8) in the 1590WFF) – into factory tapped holes. See drawings and/or photos for details. Screws use neoprene “O” rings (included). Replacement screws & “O” rings for natural finish series, stainless steel, machine type, 6-32 x 1/2” – 1590WMS100 – Package of 100 Replacement screws & “O” rings for black series, black oxide, stainless steel, 6-32 x 1/2” – 1590WMS100BK – Package of 100 Designed to meet IP65. Low side wall draft angle (2 degrees or less) for easy P.C. board mounting.