Well the brackets are good enough, but you should not rely on the listing photos as they do not specify the hole diameter. They look like maybe 6mm or 7mm in photo, but in reality the product has 9mm diameter holes, so they are the same width as a 3030 channel. This means you will need to use very wide washers to secure them in place, or a very wide head bolt. (12mm head).. Honostly I think 9mm is way to wide for the hole as the channel is 9mm wide.. It's common to use m4 or m5.. a 5mm or 6mm hole would be more appropriate!
Great seller, good quality part and fast shipping!