1.High impact resistance material:thick iron base, ABS or PC cover. 2.Automatically open and lock of lid,control by pressing the on-off button on the cover 3.white opaque and transparent blue cover are free for choice 4.Safe and full material copper terminal 5.Adjustable din-rail:move ascend and descend 6.Ultra-large space box for moving and easy wiring 7.Flush mounting and surface mounting available 8.The metal base with grounding blot 9. Most full range:from 2 way to 80 way utmost,single row to 4 rows.