1. Choose single or multi-channel fluid delivery
2. Is it easy to replace the hose
3. Is it easy to fix the hose
4. The pressure tube gap is fine-tuned by a ratchet wheel to adapt to different wall thickness hoses
5. Roller selection: 6-roller structure has a slightly larger relative flow rate; 10-roller structure has a smaller fluid pulsation amplitude
6. Whether the trigger structure is dexterous and whether it is convenient to open the card