Billiard table ivory balls from warping. The first use of electric heating was for an 18.2 balkline tournament held in December 1927 between Welker Cochran and Jacob Schaefer, Jr. The New York Times announced it with fanfare: "For the first time in the history of world's championship balkline billiards a heated table will be used..." A pool table, or pocket billiards table, has six – one at each corner of the table () and one at the midpoint of each of the longer sides ( or ). Pool tables come in different sizes, typically referred to as , , , or tables.
Billiard table balls from going in that pocket, requiring that some be moved out of the pocket manually before shooting again. Regardless of table size, the WPA standard (sometimes informally called "American-style") table has wide, angular pockets that funnel notably inward, generally 1.75 to 2.25 times as wide at the opening as the diameter of the balls, wider at the side (middle) pockets than the corners. WEPF pool (sometimes informally called "British-style" or "Commonwealth-style") is played with balls, and this type of table has smaller, narrow pockets (the width is calculated as the ball diameter multiplied by 1.6, and is consistent at