The LS Bell Hammer engine oil additives include “for kei cars” and “for regular cars.” Are they interchangeable? Is it a problem to use the regular car type in a kei car? Also, can leftover additive be reused later?

Differences and compatibility
All LS Bell Hammer engine oil additives share the same lubrication and metal surface protection technology, but differ in formulation and viscosity.
・For kei cars (Bell Hammer Light): Designed for small engines, prioritizing response and fuel efficiency.
・For regular cars (Bell Hammer Seven): Optimized for medium to large engines, emphasizing durability and stability under high temperatures.

Using the regular car type (Bell Hammer Seven) in a kei car will not cause immediate problems, but to maximize performance and engine characteristics, Bell Hammer Light is recommended.

Usage and leftover additive
The additive is not single-use. Measure 5–10% of the total oil capacity for each application.
If any remains, close the cap tightly and store in a cool, dark place away from direct sunlight or high humidity. It can be safely reused at the next oil change.

Summary
・No issue using the regular car type in a kei car, but the kei car type gives optimal performance.
・Leftover additive can be reused if stored properly.