DynoTech splined slip shafts are nothing like the heavy sloppy old school steel slip shafts that you would find in a truck or an old school hot rod or from other driveshaft manufactures.
These are all aluminum splined slip shaft assemblies designed with a tightly fitted splined assembly that lets the shaft plunge in and out but also gives the shaft the ability to spin vibration free and be incredibly strong.
The splined area comes with a boot to protect if from dust and other road debris.

Other aftermarket driveshafts on the market have a cv joint on the front, since there is no cv joint these shafts you get a substantial weight savings.  It also means you don’t have an extra 5 lbs sitting on the front of your driveshaft to put stress and loads on the output shaft and seals and you don’t have a cv joint that might wear out or need serviced.  Also gone are the rubber couplers that are found on the OEM driveshafts.
And offers 7lbs weight reduction of rotating mass.