An alternative will be offered  

https://www.easy-controlgear.com/products/ln18i-319-163763-vossloh-schawbe?_pos=1&_sid=46c6cc7ad&_ss=r

 Please note the alternative is  105mm  wide  

1x18w T8 Magnetic Ballast 85x28x42mm - Helvar - L18D