This one -

http://www.ipdusa.com/ProductsCat.aspx?CategoryID=1416&NodeID=4504&RootID=629

The metal is pretty soft. However, it does work fine if the previous installer didn't wail away at the strut top nut (not the gland nut) the way some people on this board insist you must do.
I recently removed the original strut cartridges (they were the genuine Volvo part) from my '89 wagon and I used this tool. The top nut was tight, but not so much so that I had to resort to drastic measures. It broke loose with the IPD tool and VG's clamped to the flats on the damper. The fact that they were fast but not immovable indicates to me that Volvo did not intend for this nut to be torqued to the values suggested here lately, which verge on the ridiculous.
I also used the tool and a 7mm hex bit on the torque wrench with it set to ratchet CCW. Torque value - 15 lb ft. Guess what...It's good. Not loose. Not clunky. And, in spite of what some will tell you, it's not going to work itself off. Remember, you get a new self locking nut with any insert you buy and once in place the nut turns with the bearing which turns with the damper rod. It's not going anywhere.
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'80 DL 2 door, '89 DL Wagon