Set of spare parts for any Model 90, Model 190, Model 50 or 100 or any other instrument that requires a replacement microsyringe, needles, and O-rings. The p/n 100-SPARES-90 includes (1) spare microsyringe assembly, (1) pack of 6 Viton O-rings for the microsyringe assembly, (2) replacement 22g reusable 304 stainless steel dispensing needles, and (1) pack of 10 disposable 22g 304 dispensing needles. If your instrument has a Fiber Optic Illuminator (FOI), consider the Spares Kit for U, G, and F Series.