We carry both kinds- Poly panels provide the best price point for pesos spent and watts produced because it is simply a lower cost panel to produce, the slightly costlier Mono panels produce a bit more output for the same size but at an added cost since it is more material intensive to manufacture. A majority of our customers choose Monocrystalline because it performs better in high heat, high humidity, and are more efficient – a standard 60-cell (roughly 1.6m x 1m) solar panel can get you 290W while the highest regularly available poly is only 265W in the same space.