The difference between futures polyethylene 1501 and 1510 is that the expiration dates of the contracts are different. 1501 is the contract that expires in January 2015, and 1510 is the contract that expires in February 2015, because futures are forward contracts.

Futures are completely different from spot goods. Spot goods are real goods (commodities) that can be traded. Futures are not mainly goods, but are based on certain mass products such as cotton, soybeans, oil, etc. and financial products. Assets such as stocks, bonds, etc. are standardized tradable contracts. Therefore, the subject matter can be a certain commodity (such as gold, crude oil, agricultural products) or a financial instrument.