The Quadrature LFO is generating an sine wave and 3 phase-shifted copies of it: by 90° (cosine), 180° (inverted sine) and 270° (inverted cosine).
http://aqaelektrix.com/index.php/products/qlfoThe overall condition of this Aqa Elektrix Quadrature LFO AQA ElektriX QLFO is good

If you had an Unicorn Account you could see a chart with the price development of this module and the average price asked for this module.
About the Unicorn AccountDisclaimer: Modules listed for sale on the ModularGrid Marketplace are offered explicitly by their respective owners. ModularGrid is not affiliated to the sellers and takes no legal responsibility in any transaction. The internet is a rough place and fraudulent behavior can occur. Always prefer having Buyer Protection when you make a purchase using PayPal. Don't use Friends & Family unless the seller is your friend or family!