device: 7SL87 differential/distance protection, 1 /3-pole dual-end fault protection, expandable with standard version housing type: flush mounting; BI: 27; BO: 3 4 (22ST + 8F + 4HS + 0P); I: 4 (protection); U: 4 (standard); measuring transducer inputs: 0 (20 m A or 10 V, fast), 0 (20 m A, normal); housing width: 2/3 x 19''; modules in 19" row 1: IO 208, PS201, IO205, IO209; modules in 19" row 2: ; LEDs/push-buttons: 32 LEDs; operation panel: integrated; key switch: with; display type: small display; front design: standard; auxiliary voltage:(*)