Is the billing card slingshot hole inward or outward?

Open the single card slingshot hole outwards. The opening of the open single clip slingshot adopts a trapezoidal opening with a large outside and a small inside. The outer opening 1.3mm is convenient for clamping rubber bands, and the inner opening1mm. The smaller the opening, the more rubber bands can gather. The open single-card slingshot hole is convenient to externally install the rubber band, which can be round or flat, with good directivity and windproof. The large bow door is beneficial to the force of the rubber band in front, which has little disturbance to the skin and will not hurt the rubber band because of excessive kinetic energy.