Tubes for directing steam power. This links up to other Steam blocks and can conduct steam power. Steam flows straight when possible, otherwise it turns right (and turns left if it can't do that!)
Steam Tubes price in Growtopia: sells for about 2/WL (median of 8 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: 9N5S, 3OHI, HRQD, QALDEN, TCJXB