Home / rest of / RX-29 Ro-tap Meets ARM 2.5 and ASTM D1921 Specifications RX-29 Ro-tap Meets ARM 2.5 and ASTM D1921 Specifications ARM 2.5 AND ASTM D1921 – Ro-tap® shaker, sieves, and sound enclosures manufactured by W.S. Tyler. Brass or Stainless Steel sieves are available in all US meshes and several diameters. The RX-29 Ro-tap® is the standard size sieve analyzer used by the roto industry. The RX-29 holds 6 full height 8 inch diameter sieves (screens) plus a pan and cover. Available in 110 or 220 volts, 60 Hz or 50 Hz.