Depending on their length you either get new or completely refurbished half shafts with 110mm CV flanges for the differential. The splines of the hubs are upgraded to 33mm ( for comparison all w201/w124 come with 25mm splines, and all w140/w220 come with 27mm splines).
 
These half shafts can handle up to 600ft. lbs with ease, which is almost twice more than the strongest ones installed on w124 and w201 and etc. Weight is absolutely the same as every stock w124 / w201 half shaft which means 0% more weight with almost 100% more strenght!
 
The kit includes new wheel knuckles, hubs and this is made to adopt the bigger splines which is one of the biggest problem of people with powerful M-B. What you receive is what you see on these pictures: - 2 high end refurbished 110mm CV half shafts - 2 machined wheel hubs with 5x120 and 5x112 holes and 33mm splines (30z) - 2 new nuts for tightening the wheel bearings - 2 new preinstalled bearings - 2 new uniballs preinstalled in the wheel knuckles - 2 new centering plates for the half-shaft flanges to the differential - Anti-Rust coating for the wheel knuckles
 
NOTE: 540mm - new half shafts 555mm - new half shafts 580mm - new half shafts 595mm - new 580 half shafts with 15mm spacers Please check the last picture carefully and pick your axle shaft length correctly!
 
Pick the size closest to the one you measured!
Popular chassis/diff combos: w201 with 185 mm. open differential - 555mm. w201 with 185 mm. ASD differential - 540mm. w201 with 210 mm. open differential - 540mm. w201 with 210 mm. ASD differential - 540mm. w124 with 185mm. differential - 595mm. w124 with 185mm. ASD differential - 580mm. w124 with 210mm. open differential - 580mm. w124 with 210mm. ASD differential - 580mm. 
 
NOTE: For the moment these do not feature an ABS ring