For 1 solar panel, you only need 4x rail + 4x end clamp. For 2 solar panels, you need 6x rail + 4x end clamp + 2x centre clamp. For 3 solar panels, you need 8x rail + 4x end clamp + 4x centre clamp. For 4 solar panels, you need 10x rail + 4x end clamp + 6x centre clamp.
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