How many gels are part of this? 12 as answered by another customer seems to suggest 3 jars?

You only get six pads. Fell for what looked like a 3 jar deal. Amazon had a 2 jar deal much better than this. Here is the Music Buys return policy (does not make sense to return them because of the shipping costs detailed in the fine print. Caveat Emptor! Read the fine print. Will stick to buying from Amazon warehouse from now on. Instructions from Music Buys for return: * If you are not completely satisfied with your purchase, you may return the merchandise for a refund within 30 days from the order date. If there's a problem with the order, such as shipping damage, item is defective, missing parts or wrong item was sent, please contact us via email immediately, so that we can resolve the problem for you. The returns process through the Amazon Returns Center is automated and we won't know there's a problem unless you contact us via email or phone. * Shipping and handling charges are non-refundable. If you received free shipping, the actual shipping cost incurred by Music Buys will be deducted from your refund. * Return shipping costs are the customer's responsibility. If you return an item using a prepaid return label from the Online Returns Center, the cost of return shipping will be deducted from your refund. This is in addition to the original shipping costs that are also deducted from the refund. By using the prepaid label provided, you hereby agree to these terms and conditions. No exceptions will be made. * We will not accept COD deliveries. These will be refused and sent back without notice. * A Return Authorization number (RMA#) is required for all returns. Returned packages that are received without an RMA# will be refused and sent back without notice. * A copy of the sales receipt or packing slip must accompany all returns. * Merchandise must be returned in the complete and original condition with all included packaging, parts, documentation and accessories (box, owner's manual, warranty cards, power supply, cables, etc.). * In the event that the merchandise is refused upon delivery, not returned in the original condition or with original packaging (including documentation, accessories, parts, etc), or is returned after the 30-day return period, you may be subject to a minimum 20% restocking fee in addition to shipping costs.

does it stain the snare?

Over time it will leave a small patch. If you play like I do - I sweat all over my snare, the snare will be stained anyway overtime. Underneath the moon gel will be a clean patch.