Helicoid Grease options: Japan Hobby Tool #10 and NPC FC-4 / BC-13A

Helicoid grease is a specialist item that is difficult to source and suitable options are limited. Even with options, the lens manufacturers do not disclose their greases and there are a very limited number of trusted resources that have reviewed various the greases. Two greases that are under consideration are Japan Hobby Tool #10 and NPC FC-4 (reportedly the grease used in some Nikkor lenses)