I needed this extension, because I have a table lamp at a fairly high cabinet, directing them not enough to the ground. A "classical" extension cord with an insulated box (the large connector to the springs for the mass) would not have kept tight enough because the socket of the cable hanging in the air with the power cord of the lamp. The socket of the cable from Brennenstuhl holds but securely and right heights this to be too heavy and so pull the lamp from the cabinet.
The processing can be described as very good, the delivery also ran relatively fast & smoothly into a sensible package. Given the little higher price, unlike the cheap cables of "wentronic" etc. I can only strongly recommend this cable. You just know the cross-section and know that the manufacturer places on all security-related specifications (and, so far as I know, even made in Germany).