Amazon.com : Lot of 5 Platinum Fountain Pen Converter Fit Most Platinum Pens Preppy PPQ-200 Plaisir (PQR300 x 5) : Office Products
Eyedropper converted my first platinum preppy today! :) It was fairly straightforward, though I should have gotten a slightly smaller o-ring. : r/fountainpens
Platinum Fountain Pen Converter - Gold | JetPens
Platinum Preppy Fountain Pen 0.3mm - jewoley
Amazon.com : Platinum Fountain Pen, Preppy, Medium Nib, Blue Black (PSQ-300-#3) : Office Products
Platinum converters with Preppy family : r/fountainpens