Thanks, it says how many of their weights you need but I couldn't find out how much each one weighs. 1lb each maybe? The S90 requires 2 weights.
I got my S90 and WP-DC35 with weight kit. The kits 4 plates combine weigh 0.4 lbs on my digital beer belly scale. My scale only shows one decimal, it registers as 0.2kg in case you are wondering.