Where can I get the 35mm square plate nuts that hold the roll n lock shutter system in place on pickup?

Im after the square nuts that slide into the c channel rails and clamp the roll n lock shutter down. All im after is a 35mm square threaded nut but it seems to be impossible to find one!

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).