Application segmentation maps demand to facial rejuvenation, breast augmentation, buttock enhancement, and scar repair/others. Facial rejuvenation dominates procedure volume because of broad patient eligibility, short operative time, and high repeat rates; surgeons favor low-pressure manual guns to protect delicate vascular beds, so this sub-segment sets the baseline for unit sales. Breast augmentation with autologous fat is growing fastest as patients seek implant-free options; it requires larger lumen, semi-automatic guns to inject 100-250 mL per case, driving higher syringe and disposable revenues. Buttock enhancement, although smaller in absolute procedures, uses the largest fat volumes—often >500 mL per side—creating pull for automatic guns and multi-port cannulas. Scar repair and niche reconstructive cases round out the market, typically adopting whichever device the facility already holds, hence exhibiting price-elastic demand. Together these application tiers determine the technology roadmap and pricing power within the Fat Injection Guns market size.