Sure do Matt..... or as I do, get them sent to your work.

It is funny, when purchasing through the Mauripro site, the Ronstan units get sent all the way to the US from AUS, then they ship them to you in the AUS and you still get them for more than 1/2 the price you see in shops!

Personally I have found the failure rate of the Harken ones a lot less than the Ronstan units. As mentioned above, you can adjust the Harken units but not the Ronstan. Harken are slightly bigger and a tiny big heavier and are secured with a shackle as you have mentioned. Ronstan are of course cheaper, even through the Mauripro site, so weigh up what is important for yourself....... I have used both and they both worked.