Hi all

Replacing some taps in the house. Bought some Stream Senya by Aquatica at Mitre 10 (believe it's the same as Aquatica Soluto)

http://www.aquatica.co.nz/saluto.htm

Bathroom taps was straightforward and I moved on to the gooseneck kitchen tap - but there is this thing in the box I've no idea what to do with it

It's a black hard plastic part with a flat side, and a 38.5mm diameter hole. Comes with matching double sided tape. Looks to be some sort of spacer?? or a template for cutting holes on the sink? (probably too big as the product spec says 30 to 35 mm hole for installation)

Anyone familiar with this? Thanks