* Order-related order * Technical attributes Notes HD³-ES subrack 1.0 HU, 48,3 cm ( 19 inch ), with 4 unoccupied, horizontal slots to accommodate a maximum of 4 HD³-ES modules with a height of 1.0 HU, or a maximum of 8 HD³-ES modules in height 0.5 HU, or a suitable combination of these https://media.telegaertner.com/orig/T00013A0382_HD3_ES_DE_210x297_ICv2_Online.pdf