Reference for Chullin 275:4

תפרה ונקרעה שיעורה כמוציא רמונים

R'Eliezer B'Jacob says: Of such a size as to let through a warp-clew [which weighs] one fourth part of a maneh of forty sela's.<span class="x" onmousemove="('comment',' Cf. Kel. XVII, 1, 2.');"><sup>2</sup></span>