Stackable plastic boxes for longterm storage

Can anyone recommend a brand or supplier of conservation-grade
plastic boxes as an alternative to "Really Useful Boxes", suitable
for long term storage of objects comprising mixed materials? Ideally
we need the boxes to be available in a range of sizes, including a
reasonably large size (e.g. a length of 70cm).  They need to have
lids, be stackable and able to take weights up to 20kg.  They do not
need to be transparent.

Jennifer Bainbridge
Conservator
Science Museum
Exhibition Road
London
+44 207 942 4125


                                  ***
                  Conservation DistList Instance 28:44
                  Distributed: Monday, April 20, 2015
                       Message Id: cdl-28-44-022
                                  ***