This was/is the 1963 US Repress of [r5136924] Vinyl weighs approx. 180 grams. Track A4/La Noche y Yo transforms from a Bolero to a Cha Cha. Track B1/Mi Bomba Sonó IS NOT a Bomba, it's Guaguanco. Track B5/Mambo Infierno IS NOT a Mambo. It's played much faster. It's a Guaguanco (Salsa)