Jenjaan Quartek Corporation: A Professional Frequency Control Product Manufacturer. We are the premier manufacturer of frequency control products in Taiwan and China. Our products include Crystal oscillators (SMD), temperature compensated crystal oscillators (TCXOs), voltage controlled crystal oscillators (VCXOs), and quartz crystal units (Thru-hole & SMD). For over 25 years, our dedicated team of professional technicians and technical support staff have been creating reliable, high-quality products that continuously exceed our customer’s expectations. NSK is the trademark name for Jenjaan Quartek Corporation, known for our excellent reputation in producing a quality of merchandise that is unmatched, in addition to our friendly and helpful support staff.