LW Scientific Simple Polarizing Gout Kit fits i4 only. Gout is a type of arthritis that can occur when uric acid builds up in blood and causes joint inflammation. Gout is caused by Sodium Urate Crystals which are needle-like with sharp edges with strong birefringence. Pseudo-gout (rheumatoid) is caused by Calcium Pyrophosphate Dehydrate Crystals (CPPD) which are small rods squares or rhomboids with weak birefringence. Utilizing a Uric Acid control slide for reference the user can easily determine which crystals are present in the synovial fluid by observing the color shift as the First Order Red Compensating Lens is rotated. The Gout Kit is an economical and simple alternative to a fully polarizing microscope.When used with the i4 Infinity microscope the Gout Kit is a valuable tool for identifying crystals in synovial fluid. Specifications for LW Scientific Simple Polarizing Gout Kit: Manufacturer: LW Scientific Color: Black Features of LW Scientific Simple Polarizing Gout Kit Simple to use Works with the I4 microscope Fraction of the cost of a fully polarizing Rheumatology microscope Package Contents: LW Scientific Simple Polarizing Gout Kit Uric Acid control slide LW Scientific I4P-POL7-GOUT: Simple Polarizing Gout Kit fits i4 only