Allan deviation σ(τ) = 2.7×10-11 T-1/2 for long life version and σ(τ) = 8.5×10-12 T-1/2 for high performance version  Front or Rear access connectors  3U high (133mm / 5.24”) — less than 200mm depth, compatible with ETSI and 19” standards  Accuracy better than ±1×10-12 / ±5×10-13 for high performance version  10 MHz low noise direct output  Programmable 1 / 5 / 10 MHz TTL output  10 years warranty on cesium tube (3 years for high performance version)  Redundant DC power supply inputs  Remote control and monitoring via RS232 (fully manageable locally and remotely using SyncView Plus management system.