Spin locks are absolute junk.
I have a heap of DB's in my gym, from 2kg to 45kg in pairs, a few doubles, plus singles of
36kg
41kg
50kg
55kg
I also have a set of Olympic handles to make up huge weights. Once you own the DB's, you'll never need to replace them, I've had mine for 15 years. If your serious about training, and enjoy training at home, its a good buy, as long as you can afford them
PTC what do you think about the rubber hex dumbells from gymdirect? That is what I am thinking, as I can build up my collection as time goes on.