This is a simple hand tool to use with a circular saw to help archieve straight cuts ,should be usable with most of the circular saw brands.

For assembling you need 2x M6x20mm Socket head bolts and 2xM6 nuts.

After assembling adjust the guide to fit your circular saw by putting this tool against saw blade like this and tighten two bolts.

Mark where you want to cut the wood and place this tool on the mark:

Then do the cut and you should have a straight cut on the mark: