Volvo Penta Early D3 air filter P/N 21646645. This air filter 21646645 is also used on some AD31, AD41 engines. This is the round air filter and not the square version.
To tell the difference, for an AD31 or AD41 engine which may use either part, part number 858488 has a screw-on air filter cover and 21646645 has a clip-on cover.
Volvo Penta Part No: 21646645
For: D3-130A-A, D3-160A-A, D3-110I-A, D3-130I-A, D3-160I-A
For: Some AD31, MD31, AD41 and TAMD41 engines.