JMT series are oilless types where special non-lubrication material are formed between steel body and spherical inner ring.
These bearings are mainly applied for smooth tilting motion and are highly stable and semi-permanent without lubrication.
JMTS, on the other hand, have the same specifications as JMT, but are made of stainless steel.
If you still supply lubricants regularly, we recommend you to use oilless rod end bearings.