Philips recommends this official Philips shaver head for Series S9000 and Series S9000 Prestige  models:

• Series 9000 Prestige Models; SP9820/12, SP9840/31, SP9860/13, SP9860/16, SP9861/16, SP9862/14, SP9863/14, SP9871/22, SP9872/15, SP9872/22, SP9883/35 
• Series 9000 Models; S9031/26, S9111/43, S9211/12, S9211/26, S9982/54, S9982/59, S9985/35, S9985/50, S9986/59, S9986/63, S9987/55, S9987/68, 
• Series 9000 Limited Edition Models: MVL9998/78, SW9700/67
• Series 9000 SensoTouch Models: RQ1250/17, RQ1250/22, RQ1251/22, RQ1260/16, RQ1260/17, RQ1260/22, RQ1261/17, RQ1275/17, RQ1280/16, RQ1280/21, RQ1285/22, RQ1290/23

Philips, the manufacturer have discontinued the SH90 and SH98 heads (SH90/70, SH98/70, SH98/70), and have developed the SH91 replacement heads that are compatible with all Shavers Series 9000 (SH90) and with the Series 9000 Prestige (which previously had used SH98 replacement heads).