Arista EDU Ultra 400 is Fomapan 400. Good film but definitely not Tri-X. As Matt noted, Arista Premium 400 is only available in 35mm (and that will be gone as soon as Freestyle's stock runs out). The only way to get Tri-X in 120 medium format is to buy Kodak. In that case Adorama or BHPhoto are less expensive than Freestyle.