CREATE TABLE table_24840 ("Type" TEXT, "Registration" TEXT, "Design" TEXT, "Construction" TEXT, "Service" TEXT, "Construction date" TEXT, "Conformity to original design" TEXT, "Interest" TEXT, "Number existing in Switzerland" TEXT, "Number existing worldwide" TEXT, "Status" TEXT)

What are all types where registration is HB-OPU?
SELECT "Type" FROM table_24840 WHERE "Registration" = 'HB-OPU'
SELECT "Type" FROM "table_24840" WHERE "Registration" = 'HB-OPU'