Simplify the following text for a Grade 15 native English-speaking person.
Original: Some bassists use both fretted and fretless basses in performances , according to the type of material they are performing , as with Pino Palladino , whose performance on the fretless bass during the 1980s made him a highly desirable session player backing high profile musicians that included Eric Clapton and David Gilmour .
Simplified: A bass guitar without frets is called a fretless bass guitar , and are favored by some bassists : for instance , Pino Palladino , whose performance on the fretless bass during the 1980s made him a highly desirable session player backing high profile musicians like Eric Clapton and David Gilmour .