1644UC1F.34 New Chomerics (Division of Parker Hannifin), Cho-Seal / Choseal, Electro-Conductove / Electro Conductive / Electromagnetic Interference (EMI) Shielding, Silicone Rubber Gaskets / Washers, Part Number 19-04-22222-12730-30, Customer Part Number RF401878. Each bid quantity is for a Lot of One Hundred (100) Pieces. You may bid / buy any number of lots, up to the total quantity available above. These were purchased at an electronics surplus liquidation recently. They were brand new in the original factory bags until we rebagged them in 4-mil ziplok bags for resale. At first glance, they look and feel like ordinary rubber washers. They are soft and pliable enough to be twisted and bent; although they are not quite as tough as NBR and EPDM rubber. Upon closer inspection, a bag of these is noticeably heavier, and they have a slight metallic sparkle when examined under magnification. This is due to the high metal content which provides their electroconductive and EMI shielding properties. As you probably know, Cho-Seal washers are difficult to find when you’re looking for them, and very expensive when you do. Best I could tell, these are Cho-Seal type 1273: Filler and Binder: silver-plated copper in silicone Equipment Shielding Requirements: 80-105 dB — Material of choice for high-end commercial applications — Highest performance material in noncorrosive environments According to the calipers Outside diameter: .535″ Inside diameter: .185″ (fits snugly on a #10 english or M5 metric machine screw) Thickness: .122″ According to the manufacturer: CHO-SEAL 1273 Conductive Filler: Ag/Cu Elastomer Binder: Silicone Volume Resistivity, ohm-cm, max., CEPS-0002a: 0.004 Hardness (Shore A) ASTMD2240 (Q/C): 65 +/-8 Specific Gravity (±0.25): 3.7 Tensile Strength, psi (MPa), min. ASTM D412 (Q/C): 175 (1.21) Elongation, % min. or % min./max. ASTM D412 (Q/C): 75 Compression Set, 70 hrs @100°C, ASTM D395 % max., Method B (Q): 32 LowTemperature Flex TR10,min. ASTM D1329 (Q): -65C Maximum Continuous Use Temperature: 125C Shielding Effectiveness Method (1) CHO-TM-TP08a: — 100 MHz (E Field): 100% — 500 MHz (E Field): 100% — 2 GHz (Plane Wave): 100% — 10 GHz (Plane Wave): 100% Chomerics’ products help guarantee the performance of critical electronic systems as large and complex as those in passenger aircraft, as small as those in cellular handsets. Manufacturing consistency and proven reliability are why our products are specified in so many major defense and aerospace programs, as well as thousands of business and commercial applications. Product quality is no accident. By striving to build quality into every part of our manufacturing, administration, sales, marketing, customer service, facilities and product development, Chomerics has earned its excellent reputation. Since 1993 Chomerics has been an ISO 9000 certified manufacturer.