Crank Handle Required

Check to see if the diameter of the hole that accepts the spline is 11/32". If so, see our 39-114L crank handle. This works on both a left and right-handed operator. 

That's a non-trivial difference. The 39-274 has a hole that accepts 5/16" diameter splines, but this is for a very specific type of operator and I highly doubt it's what you have. The style of your handle more matches the 11/32" types, like the 39-114L. If in doubt, show us a picture of your existing operator, including the link arm(s), so we can identify it properly, and subsequently confirm what crank handle it uses. 

This still doesn't show the whole operator; but this does look like a Pella operator base to me. In that case, see our 39-109B 3/8" diameter crank handle for Pella operators. Look it over and see if this is in fact what you need.