Aluminum oxide, electrolytic capacitors, Audio capacitors, Rubycon capacitors

 EEE-FK Series 25 V 220 uF Ø 8 x 10.2 mm 105 °C Low ESR SMT Electrolytic

https://www.futureelectronics.com/p/passives--capacitors--aluminum-electrolytic-capacitors/eee-fk1e221p-panasonic-6028597