It is a feeder. A hive body goes around it.
extra hivebody needed?
I have quite similar box but it has a cover where through robbers and wasps cannot go
yes a slipping plastic surface is bad.
I rub the surfaces with sand paper. Polyurethane glue film makes surface rough too.
Present plastic boxes have been now 25 years. They have bee splended. They are 8 litres. Easy to keep clean.