High Impact means , no loss of performance due to adverse stress caused by building movement, sudden impacts, or temperature change. Dianmeter Max.: 3/4” Contact Rating: 30VDC, 0.2A, 5W Reed Form: N/O Closed Gap: 0.75” (19mm) Departure Gap: 0.82” (21mm) Max. Initial Contact Resistance: 0.150 Ω