Dell Optiplex SX280 Full polymer kit. I have seen a couple other poly kits for this machine that just replace the 6.3v 1800uFs and I think that is useless because the caps under the hard drive fail far more often than those. The 3X 6.3v 820uF are usually the first to go followed by a 6.3v 2200uF and 16v 1500uF. If your SX280 is going to be in an enclosure or a hot room this is what you want to use.
8X Nichicon LG 6.3v 1800uF to replace 6.3v 2200uF
10X Nichicon LE 2.5v 820uF to replace 6.3v 1800uf
3X Nichicon LG 16v 820uF to replace 16v 1500uf
3X Nichicon LE 6.3v 470uF to replace 6.3v 820uf under the hard drive, the other 2 MCZs are included
3X MCZ 1000uf 16v 8mmSX280 Full Poly