What is the difference between string lock tag and seal tag?

What is the difference between string lock tag and seal tag?

String lock tag means the small tags without logo,seal tags means different shape with embossed logo or depression logo,the usual order of string lock tag is 500000 pcs-1000000 pcs, cos the price is very low and many products used them. The regular order of seal tag is 10000 pcs, 50000 pcs, 100000 pcs, the clients can choose the base color,shape,logo color,cord length and so on. We usually produced this for brand name apparel.