I think it's a ronstan, anyway, when I retorfitted my N6.0 with a snuffer rig, I used one like this for the spin halyard. The second time I used it, it wouldn't hold the sheet in heavy air!
Now, I do use some kind of high tech, no stretch line, expensive line ( can't 'member the name)
I took it back to West Marine, and got one, that looked the same size, by the same manufacturer, but, on the top of the cleat,
it has the word 'ALLOY' stamped on it in plain sight.
I'm not slamming anything here, just relating personal experience.
The current one, by the same manufacturer, works GREAT!
Todd
The spinlock is made by spinlock and the first ones that came out did not have the alloy cam (the alloy cams have white letters on them). If you contact spinlock they will send you a free replacement cam. West Marine must not move some of there stock very fast and there is a lot of old design products on there shelves. Just look at there Harken stock there are very few new cabro blocks on there shelves.
Todd,
The Spinlocks are great, but be careful with heavy loads and small line. You may want to think about sewing on a sleeve of bigger diameter line (about a foot long), just where the cam bites the line. This gives a much better bite and will help keep it from slipping under heavier loads. You don't need a spinnaker to get away from you too many times, before you figure this one out.
Don
Thanks David, and Don,
As I said, they replaced the spin lock free, and now it works just fine with the alloy cleat. I thought maybe they were making both, and wanted to point out the better product.
Todd 
The new store is slowly getting filled and we now have most of the Spinlock Products ready to ship.
Ad Police: This is my site. 
Rick
It was not the line slipping, it was uncleating itself, I assume under load , but not sure since it was on the mast and got alot of slamming around with gybes and tacks and such. I will have to look at it and see if it is alloy. What is the replacement made of? It was bought at West Marine.
David Mosley
www.seacats.org
The spinlock's work well but sometimes believe it or not when you first go out on the water and pull the shute up you need to put some water on the cleat and line. Then she will hold. My memory is that the cleat wears out after a season or so on a cat. 1/4 inch spinnaker halyard would probably be best and actually easiest to handle. This cleat gets a lot of abuse.