Exceptionally thick-walled heavy green glass, totally de-seamed & finished with our trademark 'rolled 1/4 round' cut profiles, then diamond polished to jewelry standard using fine-grade micron paste resulting in a lustrous, flawless mirror finish hard-glaze shine, this bottleneck slide offers unrivalled tone & sustain over other available glass bottleneck alternatives - this is Mike's personal choice of guitar bottleneck.