diff --git a/src/mem/alloc.h b/src/mem/alloc.h
index 04eeccb..77dbe5d 100644
--- a/src/mem/alloc.h
+++ b/src/mem/alloc.h
@@ -105,7 +105,7 @@ namespace snmalloc
      * If aligned to a SLAB start, then it is empty, and a new
      * slab is required.
      */
-    CapPtr<void, CBArena> bump_ptrs[NUM_SMALL_CLASSES] = {nullptr};
+    CapPtr<void, CBChunk> bump_ptrs[NUM_SMALL_CLASSES] = {nullptr};
 
   public:
     Stats& stats()
@@ -779,14 +779,19 @@ namespace snmalloc
         auto rsize = sizeclass_to_size(i);
         FreeListIter ffl;
 
-        auto super = Superslab::get(bp);
-        auto slab = Metaslab::get_slab(bp);
+        CapPtr<Superslab, CBChunk> super = Superslab::get(bp);
+        auto super_slabd = capptr_debug_chunkd_from_chunk(super);
+
+        CapPtr<Slab, CBChunk> slab = Metaslab::get_slab(bp);
+        auto slab_slabd = capptr_debug_chunkd_from_chunk(slab);
+
         while (pointer_align_up(bp, SLAB_SIZE) != bp)
         {
           Slab::alloc_new_list(bp, ffl, rsize, entropy);
           while (!ffl.empty())
           {
-            small_dealloc_offseted_inner(super, slab, ffl.take(entropy), i);
+            small_dealloc_offseted_inner(
+              super_slabd, slab_slabd, ffl.take(entropy), i);
           }
         }
       }
@@ -1018,7 +1023,7 @@ namespace snmalloc
       }
     }
 
-    SNMALLOC_SLOW_PATH CapPtr<Slab, CBArena> alloc_slab(sizeclass_t sizeclass)
+    SNMALLOC_SLOW_PATH CapPtr<Slab, CBChunk> alloc_slab(sizeclass_t sizeclass)
     {
       stats().sizeclass_alloc_slab(sizeclass);
       if (Superslab::is_short_sizeclass(sizeclass))
@@ -1029,10 +1034,9 @@ namespace snmalloc
 
         if (super != nullptr)
         {
-          auto slab =
-            Superslab::alloc_short_slab(super.unsafe_capptr, sizeclass);
+          auto slab = Superslab::alloc_short_slab(super, sizeclass);
           SNMALLOC_ASSERT(super->is_full());
-          return CapPtr<Slab, CBArena>(slab);
+          return slab;
         }
 
         super = get_superslab();
@@ -1040,9 +1044,9 @@ namespace snmalloc
         if (super == nullptr)
           return nullptr;
 
-        auto slab = Superslab::alloc_short_slab(super.unsafe_capptr, sizeclass);
+        auto slab = Superslab::alloc_short_slab(super, sizeclass);
         reposition_superslab(super);
-        return CapPtr<Slab, CBArena>(slab);
+        return slab;
       }
 
       auto super = get_superslab();
@@ -1050,9 +1054,9 @@ namespace snmalloc
       if (super == nullptr)
         return nullptr;
 
-      auto slab = Superslab::alloc_slab(super.unsafe_capptr, sizeclass);
+      auto slab = Superslab::alloc_slab(super, sizeclass);
       reposition_superslab(super);
-      return CapPtr<Slab, CBArena>(slab);
+      return slab;
     }
 
     template<ZeroMem zero_mem>
diff --git a/src/mem/freelist.h b/src/mem/freelist.h
index 7843379..9454a2c 100644
--- a/src/mem/freelist.h
+++ b/src/mem/freelist.h
@@ -325,8 +325,7 @@ namespace snmalloc
      * Start building a new free list.
      * Provide pointer to the slab to initialise the system.
      */
-    template<capptr_bounds B> // TODO: CBChunk-only
-    void open(CapPtr<void, B> p)
+    void open(CapPtr<void, CBChunk> p)
     {
       SNMALLOC_ASSERT(empty());
       for (size_t i = 0; i < LENGTH; i++)
diff --git a/src/mem/slab.h b/src/mem/slab.h
index 42694ac..d8f8b1f 100644
--- a/src/mem/slab.h
+++ b/src/mem/slab.h
@@ -34,7 +34,7 @@ namespace snmalloc
      * page.
      */
     static SNMALLOC_FAST_PATH void alloc_new_list(
-      CapPtr<void, CBArena>& bumpptr,
+      CapPtr<void, CBChunk>& bumpptr,
       FreeListIter& fast_free_list,
       size_t rsize,
       LocalEntropy& entropy)
@@ -60,7 +60,7 @@ namespace snmalloc
 
       // Note the wide bounds on curr relative to each of the ->next fields;
       // curr is not persisted once the list is built.
-      CapPtr<PreAllocObject, CBArena> curr =
+      CapPtr<PreAllocObject, CBChunk> curr =
         pointer_offset(bumpptr, 0).template as_static<PreAllocObject>();
       curr->next = Aal::capptr_bound<PreAllocObject, CBAlloc>(curr, rsize);
 
diff --git a/src/mem/superslab.h b/src/mem/superslab.h
index 8846096..2777503 100644
--- a/src/mem/superslab.h
+++ b/src/mem/superslab.h
@@ -201,34 +201,32 @@ namespace snmalloc
       return CapPtr<Metaslab, B>(&meta[slab_to_index(slab)]);
     }
 
-    // This is pre-factored to take an explicit self parameter so that we can
-    // eventually annotate that pointer with additional information.
-    static Slab* alloc_short_slab(Superslab* self, sizeclass_t sizeclass)
+    static CapPtr<Slab, CBChunk>
+    alloc_short_slab(CapPtr<Superslab, CBChunk> self, sizeclass_t sizeclass)
     {
       if ((self->used & 1) == 1)
         return alloc_slab(self, sizeclass);
 
-      Slab* slab = reinterpret_cast<Slab*>(self);
+      auto slab = self.template as_reinterpret<Slab>();
       auto& metaz = self->meta[0];
 
-      metaz.initialise(sizeclass, CapPtr<Slab, CBChunk>(slab));
+      metaz.initialise(sizeclass, slab);
 
       self->used++;
       return slab;
     }
 
-    // This is pre-factored to take an explicit self parameter so that we can
-    // eventually annotate that pointer with additional information.
-    static Slab* alloc_slab(Superslab* self, sizeclass_t sizeclass)
+    static CapPtr<Slab, CBChunk>
+    alloc_slab(CapPtr<Superslab, CBChunk> self, sizeclass_t sizeclass)
     {
       uint8_t h = self->head;
-      Slab* slab = reinterpret_cast<Slab*>(
-        pointer_offset(self, (static_cast<size_t>(h) << SLAB_BITS)));
+      auto slab = pointer_offset(self, (static_cast<size_t>(h) << SLAB_BITS))
+                    .template as_static<Slab>();
 
       auto& metah = self->meta[h];
       uint8_t n = metah.next();
 
-      metah.initialise(sizeclass, CapPtr<Slab, CBChunk>(slab));
+      metah.initialise(sizeclass, slab);
 
       self->head = h + n + 1;
       self->used += 2;