You need 2 pairs of hands to attach this thing to the bike. We needed to drill a hole on one of the center bars so the 2 bars can be screwed together.If I knew this beforehand, I would have returned it in a heartbeat. However, we have already installed the 2 bars on the bike before we realized the lack of hole on one of the bars. Either we got a defective one or company who produces this does not have a quality inspection procedure.I would have given this product a zero star had it not been that my child absolutely loves to ride with me using this.For all of you reading this, get the i-bert-safety-seat available here on Amazon or on ebay. It's more expensive but a lot easier to install and more comfortable for the biker (this is according to a friend who bought the ibert.)