I have a "The Open University Sound Level Indicator" available to purchase.
It has never been used and has just been sitting its original box in storage.

THINGS YOU NEED TO KNOW ABOUT THIS EBAY LISTING: 
Type CS 15
Manufactured by Castle Associates, Scarborough, Yorkshire, UK

Cosmetically, the sound level indicator is neat and tidy.
One side does have some slight surface rust marks on the outer casing ( please see the second last photo ).
The original box is well worn and has been sitting in storage for many years.
The last photo shows the actual size of the sound level indicator in comparison to a Solo can.

Please see all photos attached to this eBay listing ..... 

PICK UP IS IN THE HEART OF BENDIGO, VIC 3550.

THE PREFERRED PAYMENT METHOD IS CASH UPON PICK UP ......

THANKS HEAPS FOR TAKING OUT THE TIME TO READ THIS LISTING + PLEASE CHECK OUT MY OTHER LISTINGS THAT ARE CURRENTLY NOW RUNNI