3/4" to 1" shaft adapter question

#1
3 4" to 1" inch w Step Key Gas Engine Pulley Crank Shaft Sleeve Adapter Predator | eBay
Has anyone used one of these?
I want to run a 40 series on a 3/4" shaft. The question is the key. I know it has the key to go onto the 3/4 shaft and into the adaptor 1/4 slot. It is hard to tell from the pic but does the key supplied stick up to lock into the driver when it slides on or is it recessed still a little to allow a second key to go in? Does the 40 series come with the internal key installed or is it seperate?
 
#2
40 driver needs a separate key. Looking at that adapter, it is chamfered and scales out larger than a standard 3/16 key. I bet it splines the clutch with the adapter with that single key.
 
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