After over 80 years, Nilsson Electrical Laboratory has closed their doors and is no longer making cathodic protection related products.  If you're in the market for a Nilsson instrument, we suggest the following alternatives:

A Nilsson model 400 soil resistivity meter:
M.C. Miller model 400A	M.C. Miller model 400D	T&R model SR-2

A Nilsson model 830 current interrupter:
M.C. Miller model CI-30	M.C. Miller model JR-1	T&R model CI-50

A Nilsson model 715 pipe and cable locator:
T&R model 505 Go-Fer	Fisher model TW-6	T&R model PD