I got one like this from JC Whitney:

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Has a nice digital RPM and advance readout. Clips onto the #1 plug wire. The advance feature is nice as you can use the easier to see TDC mark for setting the timing instead of the smaller one at 5BTDC (22R/RE) and if you want to vary the timing outside 0 or 5 degrees, you don't have to guess how many degrees you are setting it to.