Needle length 0.25 mm,Be sure to choose the right port for your equipment before purchasing!!!This model is threaded interface. Each cartridge is individually packed. The needles is single use, please do not use them with others. This model is available in various sizes: 9/12/24/36/42 Pin. Our professional and caring customer service team will respond positively and give you proper solutions within 24 hours. We sincerely hope that with our sincere, enthusiastic and efficient service, we can help you overcome all the problems encountered.