Harken 45mm Double Element Block w/Swivel [6238]45mm Double Element Block with Swivel Element blocks introduce sideplates that combine forged aluminum and compound curves for strength. They are simultaneously contemporary and very robust. Elements design pairs the minimum amount of metal required to protect the sheave with a proven journal bearing. So size for size, Element is priced significantly lower, than our previously least expensive blocks. Sideplates are hardcoat anodized to resist