Featuring an industry-leading 1500 lb (680 kg) equipment load, the Z4-Series SeismicFrame® can also support an additional 100 lb (45 kg) top load for cabling. This cabinet was tested by a Telecommunications Carrier Group and ISO 17025 certified Independent Testing Laboratory (ITL) to meet the Telcordia Technologies GR-63-CORE, Issue 4, April 2012, Sections 4.4 per Zone 4 requirements. GR-63-CORE seismic testing includes a series of physical shaker table tests, during which a loaded cabinet is placed through simulated earthquake conditions. Zone 4 testing includes the most severe test conditions, in which the cabinet must perform with limited movement and survive the test without permanent structural or mechanical damage, ensuring the internal equipment is not damaged.