Pins are great, no question about it. But there are projects where we like to use Wonder Clips of Japanese manufacturer Clover. The clips are very popular and are used whenever several, thicker layers of fabric have to be pinned. Although the market is flooded with cheap imitator products, we recommend the original.
The Clover clips can be opened with little effort and clamp reliably. This article consists of 24 green Jumbo Wonder Clips with the standard dimensions 5,5cm x 1,1cm.