The LFXTAL003519 is a Crystal with resistance welded, hermetically sealed in an inert atmosphere, glass to metal seals on leads and lead wires are mounted onto a plastic former to create a gull-wing mount. The HC-49/4HSMX series crystal with shock 3 times in each of 3 mutually perpendicular planes and vibration 30mins in 3 mutually perpendicular planes.