Hi Rita, Thank you for your enquiry. The Safety 1st Extension Straps are designed to attach to and lengthen the upper tether strap on a restraint when additional length is required to connect to an anchor point in vehicles such as vans, station wagons, hatchbacks, etc. Car installation is free at our Baby OnThe Move stores when a restraint is purchased with Baby On The Move. However Installation fees are at the franchisees/stores discretion when a customer has requested to price match or is looking to install a seat purchased elsewhere. Sadly, not all car seats fit all vehicles. There are many factors that affect a child restraint fitting a vehicle such as length of seat belt, position of seat belt buckle on a long stem, contours of vehicle seat, height of passenger and space allowed behind the seat for rear facing and size of child car seat may just be too big for the vehicle. Due to this we always recommend contacting your nearest store. If you follow the link https://www.babyonthemove.co.nz/store-locations/ this will take you to our online store finder where you can find contact details for your nearest Baby On The Move Store. Here, one of our expert Car Restraint Technicians can assist in helping you with installation of this seat. We hope this has helped with your query.