These are 37mm(1 1/2") thick and have been machined from S52 Grade hot drawn seamless steel tubing by a specialist company that machine precision parts for Eaton Axles and JCB among others , they have been designed to be stronger than anything currently available in order to withstand extreme offroading as I have had them made in order to use a set on a Fourtrak challenge truck I am building for next year with 33" or 35" tyres. Of the 5 sets I have had made 1 is mine, 2 are pre-sold but 2 are still available at £170 + Vat per set of four. I appreciate that they are very expensive but you won't find anything stronger or better made for any vehicle on the market today. Check out QT Services website, their similar spacers for landrovers are just as expensive and they have volume sales. They will be on the website this weekend and if there is any interest I may have more made but if not these will be the only ones as due to the high cost of the material and machining there is little margin in them even at this price.
best regards
Dave
Blood Red Offroad Ltd
www.bloodredoffroad.com