Calibration Weight 100g Stainless Steel with Case. Have a Questions? In North America 1-800-535-3751 International 1 519-473-1953 Open Mon-Fri 8 am-5 pm EST
I bought one off ebay, found a good deal on used class 1 Troemner.
As far as "need" though, it's not super critical how accurate to the 0.0001 the calibration weight is. Reloading is much more about precision than it is about accuracy... ie. is your load the exact same as when you developed it last year, rather than whether it matters if your load is 42.42 grains vs 42.50 grains in absolute terms against some scientific standard.