The following is NLGI classification and comparison of each grade with household products of similar consistency.
NLGI number = Appearance = Consistency food analog
000 = fluid = cooking oil
00 = semi-fluid = apple sauce
0 = very soft = brown mustard
1 = soft = tomato paste
2 = "normal" grease = peanut butter
3 = firm = vegetable shortening
4 = very firm = frozen yogurt
5 = hard = smooth pate
6 = very hard = cheddar cheese
Common greases are in the range 1 through 3.
NLGI No. of 000 to 1 = used in low viscosity applications. Like gear drives operating at low speeds and open gearing.
NLGI No 0, 1 and 2 = used in highly loaded gearing.
Grades 1 through 4 are often used in rolling contact bearings. Greases with a higher number are firmer, tend to stay in place and are a good choice when leakage is a concern.