Tree Lite Sprockets
Made for BMX bikes, but the fixed gear world has taken a liking to the Tree Lite Sprockets. This sprocket uses your normal heat treated steel, and is splined for the profile cranks, although you can use with other types of cranks. Great thing is, you will not need to use a sprocket bolt. Available at Ben’s Cycles in a 42t and 39t. Via Prolly is Not Probably.