This is a replacement item. They are the two metal attaching rails that mount a Lee lens hood to a Lee filter holder. However, if you have a combined Lee filter holder/hood, these rails can be added to make it an accessory hood for a standard Lee holder.
I had to convert a LEE bellows and you were the only store that stocked this item and it was easy to place the order on the internet.
All Lee products are of the highest quality. Product as described. However, be aware that mounting using rails verses as part of an integrated foundation can lead to vignetting