Link is a way to save your payment and address details and use them over many websites. It is built and managed by Stripe nothing to do with us at www.emergency.lighting.
From Link.com
Save your payment information, and we’ll auto-fill your saved card details, addresses, and phone numbers for all future purchases on Link-enabled sites. You’ll get a chance to review your order before clicking to confirm your purchase.
Have a look and sign up with them. Your checkout experience will be much faster in the future, not just for us but many other sites too.