Spring Clip Embroidery Hoop 3" (7 cm). A spring clip frame can be used for any type of embroidery, but is particularly suited to free machine embroidery as the material being stitched can be quickly moved. Unclip the hoop by squeezing the metal grips together. Place your material over the plastic hoop, squeeze the metal ring and place inside the plastic hoop and let go. Your fabric is instantly gripped in the hoop.