3 pcs wok ring: 2 pcs a & 1 pcs b1.this wok ring with non-sharp edge on both end is best useful for round bottom wok to use. universal size for gas stove fry pans. for round bottom woks, wok ring should smaller than the desired wok diameter.2.universal size for gas stove fry pans. for round bottom woks, wok ring should smaller than the desired wok diameter. 3.wok ring has a durable construction, perforated sides on a flat steady rim. wok rack can be use to support woks when cooking on a regular range.4.with this ring, narrow side down, heat wok on small fast electric burner. it is power-frugal, heat raises and drops quickly, and food cooks as it would on gas burner. all coils are covered, so all energy is used. ring fits outside coils perfectly.5.flat-bottom wok sits close enough to absorb all heat. space dissipates heat all over wok, so food does not burn. space is small, so flat bottom and flat coils bump and limit wok movementGrooves on the Bottom. As long as your stove grates have four prongs at 90 degree intervals it will fit, keeps the wok stable so you don't have to worry about it toppling overIt fits stove that has perpendicular crosshair style grates, works with different sizes pots/pans with round/Flat base, a round bottom wok. Also fit for a round bottom wok on a gas stove with conventional gratesA rack to stabilize the wok when cooking. It has perfect grooves on the bottom so it doesn't slideAs long as your grates form a cross it will work. It has 4 notches that easily attach to the stove top, good for wok pan, milk pot(bottom diameter more than 3.94inch/10cm)Colour:blackMaterial:cast iron + stainless steelOuter diameter: 21.5cmsize:21.5 x 24.5cmPackage Contents:3 * Wok RingOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.